Apparatus for sorting ferrite cores

ABSTRACT

An apparatus for sorting ferrite cores comprising a sorting unit, a measuring two-wire probe, means for crushing the defective ferrite core coupled to the sorting unit, the measuring two-wire probe comprising separate conductors, one of which is a circuit conductor supporting the ferrite cores to be tested, which are strung thereon, and extends through means for piece-bypiece feeding of the ferrite cores, and the other comprises a needle of a single-wire probe which is operatively connected to an intermittent motion drive of means for piece-by-piece feeding of the ferrite cores and electrically coupled to a tester of the apparatus. The apparatus herein described simplifies the sorting of ferrite cores on the basis of their electrical parameters and promotes for more reliable sorting. The apparatus may be used in testing ferrite cores of any size including the superminiature cores and is directly applicable in the production line in manufacturing memory stacks and matrixes.

United States Patent Burkin et al.

CORES Filed:

APPARATUS FOR SORTING FERRITE Inventors: Jury Alexandrovich Burkin,

Tsvetnoi proezd, 29, kv. 24; Jury Emelyanovich Seleznev, Vcsenny proezd, 4-a, kv. 16, both of Novosibirsk, U.S.S.R.

Dec. 5, 1973 Appl. No.: 422,070

Foreign Application Priority Data Dec. 11, 1972 U.S.S.R 1855278 209/73, 81,81 A; 324/158 P, 34 MC; 221/312 A References Cited UNITED STATES PATENTS Rajchman et al 324/34 MC Rajchman et al 324/34 MC sweeney 324/34 MC Henken 209/81 R 51 May 13, 1975 Primary Examiner-Allen N. Knowles ABSTRACT An apparatus for sorting ferrite cores comprising a sorting unit, a measuring two-wireprobe, means for crushing the defective ferrite core coupled to the sorting unit, the measuring two-wire probe comprising separate conductors, one of which is a circuit conductor supporting the ferrite cores to be tested, which are strung thereon, and extends through means for pieceby-piece feeding of the ferrite cores, and the other comprises a needle of a single-wire probe which is operatively connected to an intermittent motion drive of means for piece-by-piece feeding of the ferrite cores and electrically coupled to a tester of the apparatus. The apparatus herein described simplifies the sorting of ferrite cores on the basis of their electrical parameters and promotes for more reliable sorting. The apparatus may be used in testing ferrite cores of any size including the superminiature cores and is directly applicable in the production line in manufacturing memory stacks and matrixes.

1 Claim, 1 Drawing Figure APPARATUS FOR SORTING FERRITE CORES The invention relates to the production process of manufacturing ferrite cores for computer memory stores, and more particularly to an apparatus for sorting ferrite cores.

The invention may be used for commercial-scale sorting of ferrite cores of any size, and especially in testing the electrical parameters of modern superminiature cores of the outside diameter of 0.3 mm and smaller which cannot be fed into the testing zone of a test bench by means of vibratory feeders since these ferrite cores exhibit the properties of dust particles A known apparatus for sorting ferrite cores comprises a vibratory feeder. This known apparatus is provided with a ferrite core batcher in the form ofa hollow tube, the cores being fed into the tube by means of a vibratory drive. The tube ensures piece-by-piece gravity falling of appropriately positioned ferrite cores. Arranged at the tube outlet is a fixing device, wherein each ferrite core is placed in the face of a measuring probe comprising a needle formed of two insulated conductors. This probe in inserted into the ferrite core hole, and after being passed therethrough, it is shortcircuited with electric contacts of a tester disposed therebehind. A required sequence of current pulses for field reversal of the ferrite core is passed through one conductor of the measuring probe, and the other conductor is used to read from the tester amplifier the signals induced by the field reversal of the ferrite core which are indicative for the ferrite core being tested. The apparatus is provided with a sorting unit and collecting hopper for finished and defective ferrite cores.

This known apparatus exhibits the following disadvantages: the two-wire measuring probe is a complicated precision device to be used in testing conventional miniature ferrite cores. In addition, it is hardly possible to make the probe for modern superminiature ferrite cores with the inside diameter of 0.1 mm and smaller. The probe is subject to inevitable damages in case of the presence of a fragment of a ferrite core in the zone of the measuring station, as well as in testing a ferrite core with an excenter hole or without any hole at all (technological fault) and even in hitting upon two ferrite cores. Contamination of the measuring station with ferrite dust and the use of a vibratory batcher result in low reliability of the apparatus. The abovementioned disadvantages make such apparatus absolutely inapplicable for sorting ferrite cores of an outside diameter of less than 0.3 mm.

Manual sorting of ferrite cores based upon their electrical parameters is being also used up to now. The manual sorting of ferrite cores consists in that several ferrite cores are scattered over a metal plate connected to a tester, and a singlewire electric circuit is completed through the ferrite core being tested by means of a sharp-pointed needle attached to an end of a flexible wire connected to the same tester, the needle being inserted by hand into the ferrite core hole until it contacts with the metal plate. This circuit ensures the transmission of the test sequence of current pulses and signals of the field reversal of the ferrite core, said signals being read out on the oscilloscope screen. Depending upon the oscilloscope readings, the operator places the tested ferrite core into one of the two boxes located adjacent the edges of the metal plate using the same needle for that purpose.

Apart from the eye strain, this sorting method is deficient in low check accuracy which is due to the indirect test method using only one conductor, as well as to the individual ability of the operator.

Prior art methods of testing ferrite cores are also deficient in that after the sorting the ferrite cores are available in bulck, whereas the majority of the production steps in the manufacture of memory stacks and matrixes from ferrite cores require that the cores should be strung on a wire, and during this operation the fractures and damages to the tested ferrite cores may occur, as well as accidental presence of defective ferrite cores or of ferrite cores of other groups may take place.

It is an object of the invention to provide an apparatus for sorting ferrite cores on the basis of their electrical parameters which is simple and reliable and permits to mechanize the process of sorting of superminiature ferrire cores including those of the minimum possible size, while ensuring the sorting of the ferrite cores directly strung on a circuit conductor.

The invention consists in that an apparatus for sorting ferrite cores comprising means for piece-by-piece feeding of the ferrite cores to a measuring station for testing the electrical parameters of the ferrite cores, a two-wire probe aranged to extend through each of the ferrite cores and to be short-circuited therebehind with the contacts of a tester, said tester feeding check signals of the test pulses through one conductor of the probe and reading'out the signals of the field reversal of the ferrite core from the other conductor of the probe, and a sorting unit serving to classify the ferrite cores into those finished and defective, according to the invention is provided with electromagnetic means for crushing the defective ferrite core, which is coupled to the sorting unit, while the measuring two-wire probe is made of separate conductors, one of which is a circuit conductor supporting the ferrite cores to be tested strung thereon and extends through means for pieceby-piece feeding of the ferrite cores, and the other comprises a needle of a single-wire probe which is operatively connected to an intermittent motion drive of means for piece-by-piece feeding and fixing of the ferrite cores and is electrically coupled to the tester of the apparatus.

The apparatus according to the invention simplifies the sorting of ferrite cores based upon their electrical parameters and makes it more reliable. The apparatus may be used in testing ferrite cores of any size including the superminiature cores and is directly applicable in the production line in manufacturing memory stacks and matrixes. The apparatus enables the sorting of ferrite cores under the conditions the most similar to the real operating conditions, that is in the presence of the interference induced from the adjacent ferrite cores as if stacked on the coordinate bar, as well as in the presence of the same circuit conductor which is used to make the matrix coordinate bar.

The invention will now be described with reference to an embodiment thereof illustrated in the accompanying drawing showing a diagrammatic view of the apparatus according to the invention in combination with a block diagram of the electronic tester.

The apparatus for sorting ferrite cores comprises means for piece-by-piece feeding of ferrite cores 1 to a measuring station 2, which means is made in the form of a rotatableshaft 3 having sockets 4 for engaging and fixing the ferrite cores 1. The rotatable shaft 3 is embraced by a slightly tensioned, circuit conductor 5 supporting the ferrite cores 1 to be sorted, which are preliminary strung thereon. The circuit conductor 5 is at the same time one of the conductors of a two-wire probe, and for that purpose the conductor 5 is connected behind the ferrite cores being tested to clamping terminals 6 and 7 of a tester 8 which feeds check signals of the test pulses and reads out the signals induced by the field reversal of the ferrite core 1 being tested. Contacts 7 of the tester 8 are connected via a two-wire circuit 8 to the terminals 6 and 7. The tester 8 is electrically coupled to a sorting unit 9 serving for sorting the ferrite cores 1 into those normal and defective.

The apparatus also comprises electromagnetic means 10 for crushing the defective core 1 which is directly adjacent to the ferrite core 1 located at the measuring station 2, said means being electrically coupled to the sorting unit 9 via a two-wire circuit 10'. The apparatus is also provided with the second conductor of the twowire probe comprising a needle 11 of a single-wire probe which is operatively connected to an intermittent motion drive 12 of means of piece-by-piece feeding of the ferrite core 1 by means of a slotted crank plate 13 and a pin 14 engaging with the slotted crank plate 13, the ferrite cores being arranged in a plane other than the plane extending through the intermittent motion drive 12 of means for piece-by-piece feeding of the ferrite cores 1. In this embodiment the intermittent motion drive 12 comprises a Geneva mechanism having a driving member 15 rotated by an electric motor through a shaft 15 and meshing with a driven member of the mechanism, that is with a Geneva wheel 16, the number of teeth of the Geneva wheel 16 being equal to the number of the sockets 4 of the rotatable shaft 3 so as to enable the piece-by-piece feeding and fixing of the ferrite cores 1. The electric motor is not shown in the drawing.

The needle 11 of the single-wire probe is electrically coupled to contacts 16' of the tester 8 via a flexible conductor 17, a two-wire circuit 17' and a contact terminal 18 facing the point of the needle 11 behind the hole of the ferrite core 1 being tested which is at the measuring station 2. The slotted crank plate 13 supporting the probe needle 11 fixed thereto is mounted in a longitudinally extending guide member 19 parallel with the probe needle axis, the operative connection between the intermittent motion drive 12 and the slotted crank plate 13 being synchronized in such a manner that there is a time interval between the movement of the ferrite core 1 to be tested and that of the probe needle 11.

Now the reference is made to the principle of the operation of the apparatus for sorting the ferrite cores 1 on the basis of the electrical parameters, the cores being strung on the circuit conductor 5.

Prior to the beginning of the operation the ferrite cores 1 to be sorted are strung on the circuit conductor, the number of ferrite cores 1 corresponding to one coordinate bar in a memory matrix or stack to be made I of these ferrite cores 1 is counted, these cores 1 are separated on the conductor 5 and the length of the conductor 5 sufficient to manufacture such coordinate bar of the memory matrix or stack is then cut off from the end of the conductor 5. The coordinate bar in the memory matrix or stack is not shown in the drawing. This length of the conductor 5 together with the ferrite cores 1 strung thereon is arranged to pass around the rotatable shaft 3, all the ferrite cores 1 being concentrated on one (upper) side of the rotatable shaft 3. The conductor 5 is connected with a slight tension to the terminals 6 and 7 of the tester 8. Where the ferrite cores 1 being tested are of a very small size and weight, a special weight is applied over the ferrite cores (not shown in the drawing). After that the preparation to the operation is completed.

Then the electric motor coupled to the driving member 15 of the Geneva mechanism is energized, and the member 15 is rotated in the direction indicated by the arrow. During the first half-turn of the driving member 15 the slotted crank plate 13 co-operating with the pin 14 retracts the probe needle 11 upwards, and the latter leaves the measuring station 2 so as to accommodate the first core 1 thereat. During further movement of the driving member 15 its pin 14 engages with a tooth of the Geneva wheel 16 to rotate the shaft 3 through The first, or the lowermost core 1 among those strung on the circuit conductor 5 engages into the socket 4 of the rotatable shaft 3 and is placed at the measuring station 2. At the same time the needle 11 performs a slow reciprocatory movement at the uppermost portion of its path. During further rotation of the driving member 15 it is only the needle 11, that moves downwards together with the slotted crank plate 13 supporting it. The needle 11 moves inside the ferrite core I placed at the measuring station 2 so as to extend adjacent the circuit conductor 5 extending through this ferrite core 1 and is brought in contact with the contact terminal 18 of the tester 8.

At that moment a test train of current pulses is fed through one circuit of the probe, while the other circuit is used to read out the information on the field reversal of the core 1 which is indicative of the quality of that ferrite core 1. If the ferrite core is defective, the sorting unit 9 will feed a signal to the crushing means 10, and the core 1 is crushed. If the core 1 being tested has the electrical parameters which comply with the specifications, there will be no signal fed to the crushing means 10, and the ferrite core 1 being tested will be transferred upon the next turn of the driving member 15 of the Geneva mechanism into the zone of the tested ferrite cores 1 below the rotatable shaft 3, while remaining strung on the circuit conductor 5.

Then the cycle is repeated until all the cores to be tested are sorted.

If desirable, the apparatus may be provided with a counter to count a total amount of the ferrite cores 1 strung on the circuit conductor 5, the readings of the counter being useful in identifying the counted batches of the ferrite cores on the basis of a predetermined amount of them in each batch, e.g. by painting a ferrite core 1 located at the boundary between the batches. The counter is not shown in the drawing.

The apparatus herein disclosed is simple in the manufacture and reliable in operation. The apparatus makes it possible to automatize the testing and sorting of the ferrite cores of the minimum possible size, which is of a great utility since the trend to reduce the size of the cores persists in the modern technology, while the volume of manufacture of the ferrite cores is being tremendously increased in all countries producing the computers. Only one medium-capacity computer comprises about several hundreds thousand of the ferrite cores which are to be hundred-percent checked.

What is claimed is:

1. An apparatus for sorting ferrite cores comprising a measuring station for testing the electrical parameters of said ferrite cores; means for piece-by-piece feeding of said ferrite cores to said measuring station; an intermittent motion drive of said means for piece-by-piece feeding of said ferrite cores; a tester; contacts of the tester; a two-wire probe extending through each said ferrite core and connected therebehind with said contacts of said tester; separate conductors of said measuring two-wire probe; a circuit conductor which is one of said separate conductors of said measuring twowire probe and extends through said means for pieceto said sorting unit. 

1. An apparatus for sorting ferrite cores comprising a measuring station for testing the electrical parameters of said ferrite cores; means for piece-by-piece feeding of said ferrite cores to said measuring station; an intermittent motion drive of said means for piece-by-piece feeding Of said ferrite cores; a tester; contacts of the tester; a two-wire probe extending through each said ferrite core and connected therebehind with said contacts of said tester; separate conductors of said measuring two-wire probe; a circuit conductor which is one of said separate conductors of said measuring two-wire probe and extends through said means for piece-by-piece feeding of the ferrite cores; said circuit conductor supporting said ferrite cores to be tested and which are strung thereon; a needle of a single-wire probe which is the other conductor of said measuring two-wire probe; said needle of the single-wire probe being operatively connected to said intermittent motion drive of said means for piece-by-piece feeding of said ferrite cores and electrically coupled to said tester; a sorting unit for said ferrite cores for classifying them into those finished and defective; and electromagnetic means for crushing said defective ferrite core coupled to said sorting unit. 